Motor control units for fluid pumping applications can be installed outdoors. Housings can be provided that withstand rain without allowing the electronic components of the control units to become wet, which would cause them to fail. A housing can be large and may include a heat sink, for example. The heat sink may be positioned at least partially outside the enclosure and can become wet without damaging the electronic components. Air circulates naturally through fins of the heat sink to passively cool the electronic components. However heat sinks require space and are relatively expensive.
An alternative or complementary approach to cool the electronic components is to provide a fan with upper and lower ventilation openings in the enclosure to enable the fan to circulate air through the enclosure to actively cool the electronic components. But while a fan may reduce the cost and space requirements of the motor control unit, active cooling can draw moisture into the enclosure, reducing the life of the motor control unit. Therefore, improvements are needed to maintain the internal volume of the enclosure in a dry state while also sufficiently cooling the electronic components without increasing the size or cost of the motor control units.
The background to the disclosure is described herein to explain the context of the present invention. This is not to be taken as an admission or a suggestion that any of the material referred to was published, known or part of the common general knowledge in the art to which the present invention pertains, in the United States or in any other country, as at the priority date of any of the claims.